“The trillion-dollar question has been how to start to bring salt down, and how much such an effort would cost,” Mozaffarian said in a university news release.

Study first author Michael Webb is a doctoral student in economics at Stanford University in Palo Alto, Calif. He said, “We found that a government-supported national plan to reduce salt would be cost-effective in nearly every country in the world. This was true even if we assumed the estimated costs were much greater or the benefits less strong.”

Mozaffarian, Webb and their colleagues used 2010 data to create a statistical model to review the costs and impact in 183 countries of a government-backed program that combined food industry agreements and public education to reduce salt consumption.

Such a program could lead to a 10 percent reduction in salt consumption over 10 years, the study estimated. That would save nearly 6 million life-years (a measure of the number of years lost to disease, disability or early death) currently attributed to heart disease each year. The average cost per life-year saved would be $204, the researchers said.

“However you slice it, national salt reduction programs that combine industry targets and public education are a ‘best buy’ for governments and policy makers,” Mozaffarian said.